1. Field of Invention
The present invention relates to electromagnetic pump, and more particularly to an electromagnetic pump with a frequency converter circuit, wherein the swinging speed, frequency and amplitude of the swing arms thereof are adjustable to change the suction pressure or the discharge pressure thereof.
2. Description of Related Arts
Taiwan patent application No. 092217183 “Nasal Cavity Cleaning and Atomizing Treatment Device” (hereinafter, the first prior art) discloses a device for suctioning snot, cleaning the nasal cavity and atomizing a fluid with medicine to the nasal cavity to treat the sickness of nasopharynx. The device comprises a chamber and a bladder expending and compressing to respectively draw a gas into the chamber through an inlet and discharge the gas from the chamber through an outlet. If a suction device is connected to the inlet, the device will become a device with the function of suctioning snot. If an atomizer is connected to the inlet, the device will become a device with the function of atomizing medicine. However, the power source of the device is a motor with a rotor, which rotates to drive a shaft of the motor forth and back with a predetermined distance. The quicker the rotor rotates, the bigger the suction force or the discharge force generated in the chamber is, wherein the flow increases along with the generated pressure. As the device in the first prior art is a device with multiple functions, it is safe to use it for atomization treatment; however, when it is used to suction the snot, it might hurt the nasal cavity due to the over suction force, and that when it is used to clean the nasal cavity, it might cause a choke due to the over discharge force. Besides, the motor has a lot of defects, such as high power consumption, big bulk, a lot of noise, too big suction force, too big discharge force, high-heat, short service life, unbearable of wetting. Hence, the device is not a proper power source for the medical apparatus and instruments that are required to contact with human body.
It is well known that the electromagnetic pump has several advantages, such as less weight, less noise, lower power consumption, hard to generate high-heat, no short circuit when the inlet channel or the outlet channel is blocked. Hence, the electromagnetic pump is a better choice to be used as the power source of the medical apparatus and instruments that are required to contact with human body. Taiwan patent application No. 092218142 “Gas Filler for Air Bed” (hereinafter, “the second prior art”) discloses an electromagnetic pump for transporting the gas to filling the air bed. The second prior art was filed by the applicant in 1992. Taiwan patent application No. 09307116 “Electromagnetic Pump with Swappable Drawing Direction and Discharge Direction” (hereinafter, “the third prior art”) and Taiwan patent application No. 093217312 “Easy-Clean Electrical Snot Suction Device” (hereinafter, “the forth prior art”) disclose an electromagnetic pump using gas and/or liquid due to the development made by the applicant. Referring to FIG. 1, the electromagnetic pump could only use the AC to make the swing arm 25 swinging forth and back. Around the world, the electricity for home use is generally 110V or 220V, for example the electricity supplied in Taiwan is a single-phase power source with 110V and 60 Hz. Hence, when 110V and 60 Hz AC is used as the power source of the electromagnetic pump, the magnetic field intensity generated in the electromagnetic device 27, the length and width of the swing arm 25, the magnetic field intensity of the magnetic member 26, and the elasticity of the bladder 24 are limited and coupled in such a manner that the swing speed, the swing frequency and the swing amplitude of the swing arm 25 of the electromagnetic pump 20 are fixed and nonadjustable. As shown in FIG. 1, the amplitude W4, the swing speed and the swing frequency of the swing arm 25 are retained in a fixed value and could not be changed after the electromagnetic pump is manufactured. However, the swing speed, the swing frequency and the swing amplitude of the swing arm 25 affect the suction pressure, the suction flow, the discharge pressure, and the discharge flow of the electromagnetic pump 20. It means that due to the limitations mentioned above, the suction pressure, the suction flow, the discharge pressure, and the discharge flow of the current electromagnetic pump could not be adjusted according to the required pressure and flow. However, it is a future trend to use medical apparatus and instruments with multiple functions, and thus there is a room for improvement to provide the electromagnetic pump using the gas and/or the liquid with adjustable ability in suction pressure, suction flow, discharge pressure, and discharge flow with respect to the desired functions.